$(document).ready(function(){
	var $liCur = $(".nav ul li.cur"),
	curP = $liCur.position().left,
	curW = $liCur.outerWidth(true),
	$slider = $(".curBg"),
	$navBox = $(".nav");
	$targetEle = $(".nav ul li a"),
	$slider.animate({
		"left":curP,
		"width":curW
	});
	$targetEle.mouseenter(function () {
	  var $_parent = $(this).parent(),
		_width = $_parent.outerWidth(true),
		posL = $_parent.position().left;
	  $slider.stop(true, true).animate({
		"left":posL,
		"width":_width
	  }, "fast");
	});
	$navBox.mouseleave(function (cur, wid) {
		  var $liCur = $(".nav ul li.cur"),
		curP = $liCur.position().left,
		curW = $liCur.outerWidth(true),
		$slider = $(".curBg"),
		$navBox = $(".nav");
		$targetEle = $(".nav ul li a"),
		$slider.animate({
			"left":curP,
			"width":curW
		});
	});
})
